Advancing thermal stability through positional pyrazole isomerization: Synthesis and characterization of 2’-(1H-pyrazol-4-yl)-1H,2’H-5,5’-bistetrazole and its energetic derivatives

Abstract

The development of energetic compounds with superior comprehensive properties remains a central focus in energetic materials research. By employing positional pyrazole isomerization, we have successfully synthesized 2’-(1H-pyrazol-4-yl)-1H,2’H-5,5’-bistetrazole (2) and its several energetic salts (2a-f). The synthesized compounds were characterized using nuclear magnetic resonance (NMR) and infrared spectroscopy (IR). The structure of compound 2a was further confirmed by single crystal X-ray diffraction analysis. Notably, compound 2, featuring 4-substitution on the pyrazole, demonstrates superior overall properties compared to the previously reported isomer V with 3-substitution. Among the newly synthesized salts, compound 2d exhibits exceptional thermal stability, while compound 2c shows a detonation velocity comparable to RDX. These findings suggest that positional isomerization is a promising approach for enhancing the thermal stability of energetic compounds.